1. Field of the Invention
The present invention pertains to a shaping process of a hollow object made of glass such as a bottle, a flask, a jar, etc., and a device for implementing such a process.
2. Description of the Background
The traditional processes, which are presently extensively used to make flasks, employ so-called individual section machines and are known under the names of the xe2x80x9cblown-blownxe2x80x9d and xe2x80x9cpress-blownxe2x80x9d processes.
These processes can be broken down into several stages. In the following, the xe2x80x9cblown-blownxe2x80x9d process, which is the most widely used of the two, is described.
The conventional xe2x80x9cblow-blowxe2x80x9d process includes the steps of:
loading: a drop or ball of glass enters due to the effect of its own weight into a first mold (a roughing mold) through its upper end which corresponds to the bottom of a final product such as a bottle, etc.;
compression: after loading, a rough bottom section closes the roughing mold; then a blast of compressed air forces the drop of glass in the roughing mold through the intermediary of the roughing mold into the lower part of the mold in which a collar of the final product is later formed; this compression also ensures good thermal contact between the drop of glass and the roughing mold;
perforation: a punch of small dimensions, taking up approximately the height of the collar and fitted at the lower part of the roughing mold, detaches from the lower part of the roughing mold, thereby leaving room for compressed air to be delivered, the compressed air pushes in front of it the hot, less viscous glass located in the vicinity of the axis of the roughing mold, while the more viscous cold glass that has been cooled upon contact with the mold remains in place; a blank or a rough mold of the final product is thereby produced;
transfer: when the blank is sufficiently cooled in the roughing mold for handling, the blank is transferred into a second mold (a finishing mold) which has a shape of the final product;
elongation and blowing: once the blank is placed in the finishing mold, the blank is allowed to lengthen for a certain amount of time before blowing in order to give the shape of the product; this lengthening stage allows the glass to be distributed throughout the product;
extraction: upon contact with the finishing mold, the glass cools quickly, and when its viscosity is sufficiently low, the product is extracted from the finishing mold.
Such a process allows one to make flasks in a large number of shapes, whether they are axisymmetrical or not.
The flasks can be classified in a non-limiting manner into two categories, particularly depending upon the type of liquid which they contain: those in which the collar includes a fillet and which are closed by a plug; and those in which the collar does not have a fillet and which are provided with an atomizer set at the top of the collar and enclosed by a cap.
Recently, certain perfume makers have requested that a new flask shape belonging to the second category mentioned above be made.
This means making a flask with the following characteristics: the outer casing, that is, the part made of glass extended by the envelope of the cap, must be included in a sphere of a certain diameter; and the collar must have a large opening, that is, it must have a considerable diameter with respect to that of the sphere.
Such a flask, and especially the part made of glass, cannot be produced in the traditional manner, because, as already stated, the atomizer, which must be set around the collar, necessarily has large dimensions and thus the cap in the shape of a spherical cover cannot be included in the extension of the spherical part of the glass body.
To overcome these problems, a shaping process of a hollow object made of glass provided with a collar and a shoulder according to the present invention, employing a xe2x80x9cblown-blownxe2x80x9d technique, includes a roughing-out phase, a transfer phase and a finishing phase, wherein during the finishing phase, the collar is partially driven into the shoulder while maintaining at least one part of the height of the collar.
Such a process according to the present invention provides an excellent answer to the problems presented above while avoiding any risk of making the glass more fragile once it has solidified.
However, this solution, while surprisingly simple, is far from obvious. To obtain controlled deformation of the desired area without thereby deforming the collar is difficult, especially due to the highly constraining tolerances with respect to the diameter of the collar.
Preferably, the driving-in stage is performed immediately after the air blasting stage which brings the glass into contact with the finishing mold, thereby benefitting from optimal viscosity of the glass in order to easily deform the glass in a highly controlled manner.
An advantageous characteristic according to the present invention is that because only the shoulder of the object is withdrawn from the mold prior to the driving-in stage, the mass of the glass necessary for making the body is left well-distributed throughout the finishing mold.
Another advantageous characteristic according to the present invention is that, immediately after the collar is driven into the shoulder, the object is blown inside. This additional blowing allows good evacuation of heat while having very little effect on the distribution of the glass inside the mold.
The present invention also pertains to a particularly appropriate device for implementing the process in accordance with the present invention.
According to the present invention, a shaping device of a hollow object made of glass provided with a collar and a shoulder includes a mold having two main shells combined with one another along a vertical axis and a blasting head connected to a circuit, wherein the blasting head includes a support structure in which a translationally movable part is installed and whose terminal part is designed to hold the collar of the hollow object.
A preferred characteristic according to-the present invention includes the terminal part of the movable piece which has an internal diameter approximately equal to the external diameter of the collar of the object.
Such a shape allows one to hold the interior of the collar, thereby avoiding the risk of marking the exterior of the collar and harming the object""s appearance.
An additional characteristic according to the present invention includes the terminal part of the movable piece which has an external shape that approximates a truncated cone.
Advantageously, the movement of the movable piece in the support structure is ensured by a pneumatic device. This allows one to control in a very precise manner the direction of the piece and monitor the precision of the driving-in action in conformity with the invention.
A device according to the present invention is particularly well-suited for use as a finishing mold of an individual section machine.
The invention also pertains to a hollow object made of glass, which is produced in conformity with the previously described process or by means of the aforementioned device.
This object is characterized by an xe2x80x9cundercutxe2x80x9d formed therein.
xe2x80x9cUndercutxe2x80x9d mean, within the scope of the invention, a shoulder line which joins the culminating point of the body at the lowest point of the collar, and is located below the horizontal when the collar is directed upward and its axis is extending along the vertical.
An object of the present invention is to provide a novel process of shaping a hollow glass object, which allows to manufacture a hollow glass object whose glass body and cap are included in a sphere of a certain diameter while the collar of the hollow glass object is provided with a large opening.
Another object of the present invention is to provide a novel device for implementing the process described above.
The first object may be accomplished by a process of shaping a hollow glass object, including the steps of roughing out molten glass into a rough mold with a collar and a shoulder, transferring the rough mold prepared in said roughing out step to a finishing mold, and partially driving the collar into the shoulder while maintaining at least one part of a height of the collar.
The second object may be accomplished by a device for shaping a hollow glass object with a collar and a shoulder, including a mold including at least two main shells combined with one another along a vertical axis, and a blasting head configured to blast at least one of air and gas. The blasting head includes a movable piece having a terminal part configured to hold the collar.